1. Field of the Invention
The present invention relates to a method for producing a Group III nitride semiconductor light-emitting device including an n-type layer having thereon an embossment in which dents and mesas are arranged in a stripe pattern as viewed from above (hereinafter such an embossment may be referred to simply as a “stripe-pattern embossment”), and a light-emitting layer which is deposited on the n-type layer so as to contour the embossment.
2. Background Art
Widely used Group III nitride semiconductor light-emitting devices have a structure including a sapphire substrate, and a Group III nitride semiconductor layer having a c-plane main surface and deposited on the substrate. In a Group III nitride semiconductor light-emitting device having such a structure, internal quantum efficiency is approaching its limit, and difficulty is encountered in greatly improving light output. Although many studies have been conducted on the electrode of such a device or the shape of chip, difficulty is encountered in greatly improving light extraction performance.
Japanese Patent Application Laid-Open (kokai) No. 2003-92426 or 2008-130606 proposes a technique for solving such a problem. Specifically, Japanese Patent Application Laid-Open (kokai) No. 2003-92426 or 2008-130606 discloses a method for producing a semiconductor device having an increased emission area and exhibiting improved light output by forming, on an embossed n-type layer, an undulated light-emitting layer so as to contour the embossment. Japanese Patent Application Laid-Open (kokai) No. 2008-130606 also discloses a semiconductor layer having a stripe-pattern embossment and a serrated cross section, in which inclined surfaces forming the embossment are m-plane surfaces (i.e., non-polar plane surfaces). Since m-plane is a plane which provides a piezoelectric field of zero, internal quantum efficiency can be improved.
However, when an undulated light-emitting layer is formed so as to contour the embossment of an n-type layer as described in Japanese Patent Application Laid-Open (kokai) No. 2003-92426 or 2008-130606, the light-emitting layer may exhibit a variation in thickness; i.e., difficulty is encountered in forming the light-emitting layer to have a uniform thickness.